The present invention relates to a method of producing cartons of cigarettes.
Cartons of cigarettes are known to be produced using flat, precut blanks, each of which is folded along yield lines to define a box housing a respective group of packets of cigarettes constituting the content of the carton.
According to one known method, each blank is folded in a U about a respective group of packets, so as to cover three of the surfaces of the group and leave a further three surfaces exposed, from each of which exposed surfaces the blank presents at least two outwardly-projecting tabs, which are subsequently folded to cover the respective exposed surface.
For folding the tabs projecting from each exposed surface, Italian Patent Application N. 3422A/90 utilizes, for at least one of the surfaces, a folding head past which the U-folded blank and the respective group of packets are fed so as to gradually fold part of the tabs squarely. Subsequently, the folding head is moved in a direction substantially perpendicular to the traveling direction of the blanks, so as to complete square-folding of the respective tabs.
Though employed successfully on cartoning machines, the above known method presents several drawbacks, mainly due to both the blank with the respective group of packets and the folding head necessarily being moved during the tab folding process, thus resulting in obvious mechanical complications and the possibility of the blank being moved incorrectly in relation to the stationary folding head.